<?php
class Common_Doctrine_Hydrator_AssociativeArray extends Doctrine_Hydrator_Abstract
{
    public function hydrateResultSet($stmt)
    {
        $data = $stmt->fetchAll(PDO::FETCH_NUM);
        $arrResult = array();
        if (count($data)) {
            foreach ($data as $arrRow) {
                $arrResult[$arrRow[0]] = $arrRow[1];
            }
        }
        // do something to with $data
        return $arrResult;
    }
}
?>

